Punch for corrugated board

ABSTRACT

Apparatus for slotting corrugated board for box partitions includes a reciprocating punch which is received in the female slotting die and in which a thin liner knife located intermediate the side walls of the male punch and extending from the end wall of the male punch initially contacts and severs the board liners to prevent stretching and tearing of the board by the male punch as the punch engages the board and moves into the female die.

I United States Patent [1 1 I 3,786,708 Mumper Jan. 22, 1974 4] PUNCH FOR CORRUGATED BOARD 2,838,112 6/1958 Feitl.... 83/622 X Inventor: Richard G. p l ee 3,293,962 12/1966 Glanarls 83/332 Wis.

Primary Examiner--Frank T. Yost [73] Asslgnee' xg a if g rgg i g Attorney, Agent, or Firm-Henry C. Fuller, Jr.

[22] Filed: Feb. 27, 1973 [21] App]. No.: 336,314 [57] ABSTRACT Apparatus for slotting corrugated board for box partitions includes a reciprocating punch which is received [52] Cl 57 in the female slotting die and in which a thin lihei [51] Int Cl B26f 1/1'4 knife located intermediate the side walls of the male [58] held oielicit":Tahitian; 345 667 punch and extending from the end wall of h male 9:058 58 punch initially contacts and severs the board llners to prevent stretching and tearing of the board by the {56] References Cited male punch as the punch engages the board and moves into the female die. UNITED STATES PATENTS 2,185,885 1/1940 Bruker et al 83/332 X 7 Claims, 6 Drawing Figures PUNCH FOR CORRUGATED BOARD BACKGROUND OF INVENTION When slotting or cutting corrugated paperboard such as double wall corrugated board, conventional slotting punches crush the corrugations flat before passing through the female die blocks and complete the slot. In addition, the outer and upper liner of the corrugated board is stretched prior to completion of the cut. This stretching open results in tears which crumble the board edges leaving small fragments which may dislodge and come loose within the box during use of the box.

SUMMARY OF INVENTION The invention provides a liner knife which projects from the end wall of the punch to sever the liners and corrugations prior to engagement with the punch which slots the partition material to the desired slot size. The liner knife thus eliminates tearing, stretching and the crumbly edges of the partitions. The liner knife can be used either with a rotary partition slotter or a reciprocating punch.

The liner knife can have either a saw tooth configuration or a beveled edge, depending on the type of corrugated board being cut or slotted.

Further objects, advantages and features of the invention will become apparent from the following disclosure.

DRAWINGS FIG. I is a fragmentary side elevational view of apparatus including a reciprocating punch head employing a punch with a liner knife in accordance with the invention.

FIG. 2 is an end view of the liner knife and punch shown in FIG. 1.

FIG. 3 is a side elevational view of a rotary slotting punch with a modified liner knife in accordance with the invention.

FIG. 4 is an end view of the knife shown in FIG. 3.

FIG. 5 is a sectional view of a prior art punch and die.

FIG. 6 is a sectional view of a punch such as that shown in FIGS. 1 and 3 in use cutting double wall corrugated paperboard, and with a modified embodiment of the liner knife.

DESCRIPTION OF PREFERRED EMBODIMENT Although the disclosure hereof is detailed andexact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. The scope of the invention is defined in the claims appended hereto.

In the drawings, FIG. I shows a reciprocating punch head 10, a punch holder 12 and a male punch 14 in accordance with the invention. The punch is secured to the holder 12 by bolts 15. The punch 14 includes a liner knife 16 which is located intermediate punch sides 18 and 20, and projects from the punch end surface 22.

In the embodiment disclosed in FIG. 1, the liner knife has a knife portion 24 which is fixed in a slot 26 in the punch 14. The liner knife 16 also is provided with a finely serrated or saw toothed edge 28. The liner knife 16 and punch end surface 22 are inclined at an angle to the longitudinal extent of the punch 14 to provide a shearing action on the corrugated board. FIGS. 1 and 2 also show a female die 30 supported in a die shoe 32 carried by a bolster plate 34. In use, the punch sides 18, 20 are received between the die surfaces 31 and 33.

FIG. 3 shows a rotary partition slotter in which a male rotary slotting punch 40 is carried by a shaft 42 and includes a punch blade 44 in the form of a circular ring segment which projects from the periphery 46 of the punch 40. The punch blade 44 includes a liner knife 48 in accordance with the invention which is located between opposed side surfaces 50 and 52 of the blade 44 and projects from the periphery or end surface 54. The blade 44 can be received in a slot 56in the punch 40 and be secured by bolts 58.

The apparatus in FIG. 3 also includes a hopper or magazine 60 which contains a supply of corrugated board partition material 62 which is supported on a table 64. A reciprocating kicker 66 feeds partition material to the punch 40. A female slotting die 70 includes an annular groove 72 which receives the punch blade 44 and liner knife 48 during the punching operation.

FIG. 5 shows a prior art punch in which the male punch is received in the female die 82. During the punching operation the compression of the double wall corrugated board 84 stretches the liner at 86 and 88 which can cause tearing, shredding and fragmentation of the board liners. Thus fragments of the liner and board are easily severed or lost from the partitions when in use to scatter debris throughout the box in which the partition is employed and also on the box contents.

FIG. 6 shows a modified embodiment of the liner knife 90 of the invention mounted in a reciprocating male punch 92 of the type shown in FIG. 1, which cooperates with a female die 94. The liner knife 90 has a beveled knife edge 96 rather than the saw toothed edge 28 shown in FIG. 1. In use of the liner knife 90, the knife initially severs the corrugated board liners 98 and 100 prior to contact of the board with the end surface 102 of the male punch 90. Thus stretching and fragmentation of the corrugated board do not occur as it does with the prior art punching operation shown in FIG. 5 when the end surface 102 engages the board. The cutting action of the liner knife 90 is also similar to that accomplished by the liner knife in the rotary slotting arrangement shown in FIG. 3.

I claim:

1. In apparatus for cutting paperboard comprising a male punch and a female die adapted to receive said male punch and including means for moving said male punch into said die, and said male punch including side surfaces and an end surface, the improvement comprising liner knife means located intermediate said punch side surfaces and projecting from said end surface to sever portions of the paperboard prior to engagement by said end surface and prevent stretching and tearing of said paperboard by said end surface as it engages the paperboard.

2. The improvement of claim I wherein said knife means has a saw tooth profile.

3. The improvement of claim I wherein said knife means has a beveled edge.

4. The improvement of claim 1' wherein said end sur-' face has a slot parallel to the side surfaces of said punch and said liner knife being fixed in said slot.

means is in the form of a circular ring segment.

7. The improvement of claim 1 wherein said male punch is mounted for reciprocating movement and said end surface is inclined at an angle to the longitudinal axis of said punch. 

1. In apparatus for cutting paperboard comprising a male punch and a female die adapted to receive said male punch and including means for moving said male punch into said die, and said male punch including side surfaces and an end surface, the improvement comprising liner knife means located intermediate said punch side surfaces and projecting from said end surface to sever portions of the paperboard prior to engagement by said end surface and prevent stretching and tearing of said paperboard by said end surface as it engages the paperboard.
 2. The improvement of claim 1 wherein said knife means has a saw tooth profile.
 3. The improvement of claim 1 wherein said knife means has a beveled edge.
 4. The improvement of claim 1 wherein said end surface has a slot parallel to the side surfaces of said punch and said liner knife being fixed in said slot.
 5. The improvement of claim 1 wherein said male punch is in the form of a circular ring segment and said knife means projects from the periphery of said segment and wherein said female die is in the form of two spaced die parts which define an annular groove for receiving said circular ring segment.
 6. The improvement of claim 5 wherein said knife means is in the form of a circular ring segment.
 7. The improvement of claim 1 wherein said male punch is mounted for reciprocating movement and said end surface is inclined at an angle to the longitudinal axis of said punch. 